Using the OBD Link MX+

[Sojourner]

Great info. Thank you for taking the time to post.

Sponsored

 

[NickAtNight]

what variables do I need to monitor?

this guy has an interesting set.

 

[NickAtNight]

Note: The default MAF (Mass Air Fuel) sensor used in the OBDLink+ display IS NOT A SUPPORTED PID for the Bronco Sport. So that one needs to change.

 

[NickAtNight]

Recreated the Speed vs RPM table for each gear. (Note: top speed is 121 mph)

	1	2	3	4	5	6	7	8
	4.69	3.31	3.01	1.92	1.45	1.00	0.75	0.62
RPM	17.87	12.60	11.48	7.33	5.51	3.81	2.85	2.35
1,000	4.7	6.7	7.4	11.6	15.4	22.3	29.8	36.1
1,200	5.7	8.1	8.9	13.9	18.5	26.7	35.8	43.3
1,400	6.6	9.4	10.3	16.2	21.6	31.2	41.7	50.5
1,600	7.6	10.8	11.8	18.5	24.6	35.6	47.7	57.7
1,800	8.5	12.1	13.3	20.8	27.7	40.1	53.7	65.0
2,000	9.5	13.5	14.8	23.2	30.8	44.5	59.6	72.2
2,200	10.4	14.8	16.3	25.5	33.9	49.0	65.6	79.4
2,400	11.4	16.2	17.7	27.8	37.0	53.4	71.5	86.6
2,600	12.3	17.5	19.2	30.1	40.0	57.9	77.5	93.8
2,800	13.3	18.9	20.7	32.4	43.1	62.3	83.5	101.0
3,000	14.2	20.2	22.2	34.7	46.2	66.8	89.4	108.3
3,200	15.2	21.6	23.7	37.1	49.3	71.3	95.4	115.5
3,400	16.1	22.9	25.1	39.4	52.4	75.7	101.3	122.7
3,600	17.1	24.2	26.6	41.7	55.4	80.2	107.3	129.9
3,800	18.0	25.6	28.1	44.0	58.5	84.6	113.3	137.1
4,000	19.0	26.9	29.6	46.3	61.6	89.1	119.2	144.4
4,200	19.9	28.3	31.0	48.6	64.7	93.5	125.2	151.6
4,400	20.9	29.6	32.5	50.9	67.8	98.0	131.2	158.8
4,600	21.8	31.0	34.0	53.3	70.8	102.4	137.1	166.0
4,800	22.8	32.3	35.5	55.6	73.9	106.9	143.1	173.2
5,000	23.7	33.7	37.0	57.9	77.0	111.3	149.0	180.4
5,200	24.7	35.0	38.4	60.2	80.1	115.8	155.0	187.7
5,400	25.6	36.4	39.9	62.5	83.2	120.2	161.0	194.9
5,600	26.6	37.7	41.4	64.8	86.2	124.7	166.9	202.1
5,800	27.5	39.1	42.9	67.2	89.3	129.1	172.9	209.3
6,000	28.5	40.4	44.4	69.5	92.4	133.6	178.8	216.5
6,200	29.4	41.8	45.8	71.8	95.5	138.1	184.8	223.7
6,400	30.4	43.1	47.3	74.1	98.6	142.5	190.8	231.0

 

[NickAtNight]

Using the same source, the engine Torque increases up to 3,000 RPM. Fit a polynomial to the data.

Once above 3,000 RPM, torque then starts to decrease with RPM. Fitted a polynomial to that regime too.

 

[NickAtNight]

Hmm. Max torque is 190.3 lb-ft at 3,000 RPM.

If we look at the torque loss at higher RPM's, we get a nice curve up to 6,000 RPM. After 6,000 RPM we take an accelerated Torque loss hit.

Torque = (190.3 lb-ft) -( RPM-3000)^2/282,141 - (RPM-6000)/15100

 

[NickAtNight]

Rewrote the low RPM equation to be from the maximum torque of 190.3 @ 3,000 RPM. So now if we are below 3,000 RPM we can use this equation ot find Torque. and if we are above 3,000 RPM we use the other equation.

 

[NickAtNight]

Engine Horsepower is Torque * RPM / 5252
- Drew a curve for 'perfect' horsepower if the engine always developed maximum torque.
- Drew the calculated horsepower curve using the above equations (which matches the supplied HP curve)
- Calculated the difference between best HP and actual HP.

 

[NickAtNight]

At 60 MPH (recorded 58.6 in log) the average Fuel/Air commanded was 0.992. The O2 sensor wide lambda meter is at 0.999. The logged Vehicle fuel rate is 0.149 lb/min while the exhaust flow rate is 2.236 lb/min. Subtracting Exhaust from Fuel means the air flow would be 2.097 lb/min. For a Fuel to air ratio of 14.132. Perhaps a bit on the richer side than the requested.

At 50 MPH (recorded 49.4 in log) the average Fuel/Air commanded was 1.004. The O2 sensor wide lambda meter 1.001. The logged Vehicle fuel rate is 0.94 lb/min while the exhaust flow rate is 1.481 lb/min. So subtracting exhaust rate from Fuel we get a mass air rate of 1.387 for a mass fuel/air ratio of 14.806.

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Youtube explanation of Volumetric Efficiency - Live Tuning. Gives a good explanation on what some of the parameters mean.

Best Torque vs Best Economy

Conversion Table - Lambda to Air /Fuel Ratio